This invention relates to an apparatus for treating waste liquor produced concomitantly with development processing of light-sensitive photographic materials using an automatic processing machine for photography (hereinafter abridged as "photographic process waste liquor" or "waste liquor") through concentration by evaporation, and, more particularly, to an apparatus for treating photographic process waste liquor through concentration by evaporation, that is suited for treating the waste liquor by installing the apparatus inside the automatic processing machine or in the vicinity thereof.
In general, the photographic processing of light-sensitive silver halide photographic materials is carried out by combining steps employing processing solutions having one or more of the functions such as developing, fixing, water washing, etc. in the case of black and white light-sensitive photographic materials. In the case of light-sensitive color photographic material, processing includes color developing, bleach-fixing (or bleaching and fixing), water washing, stabilizing, etc.
Then, in the photographic processing to process a large quantity of light-sensitive materials, there is employed a means by which the performance of processing solutions is constantly maintained by removing (while replenishing components consumed by the processing) components that may be thickened or concentrated during the processing by dissolving-out in the processing solution or by evaporation (for example, bromide ions in the developing solution, silver complex salts in the fixing solution, etc.). A replenishing solution or replenisher is supplied to the processing solution for the purpose of the above replenishing, and a part of the processing solution is thrown away for the purpose of removing the above thickened or concentrated components in the photographic processing.
Recent years, because of environmental pollution or for economical reasons, replenishing solutions for photographic development processing solutions as well as washing water which is a replenishing solution for washing are undergoing a change such that they are used in a system in which the quantity of the replenishment has been greatly decreased. The photographic process waste liquor, however, is led from a processing tank of the automatic processing machine through a waste liquor pipe and thrown away in sewerages or the like after being diluted with waste liquor of washing water or cooling water for the automatic processing machine.
However, because of tightened regulation in recent years against environmental pollution, although it is possible to throw away washing water or cooling water in sewers or rivers, it has been made substantially impossible to throw away the photographic processing solutions other than those [for example, developing solutions, fixing solutions, color-developing solutions, bleach-fixing solutions (or bleaching solutions or fixing solutions), stabilizing solutions, etc.]. For this reason, every photographic processing dealer has the waste liquor collected by dealers specialized in the waste liquor treatment by paying collecting fee, or installs equipment for pollution-preventive treatment. Such way of placing the waste liquor treatment to dealers' care may require a considerable space for keeping the waste liquor stored and may also be very expensive from the viewpoint of cost. Also, the equipment for pollution-preventive treatment may involve disadvantages such that it requires a very large initial investment (or initial cost) and a considerably large space for the equipment. Accordingly, in general, the waste liquor is collected by waste liquor collecting dealers, and made harmless after secondary and tertiary treatments. However, because of an increase in the cost for the collection, not only the fees for taking over the waste liquor is increasing year by year, but also the dealers are not willing to come to collect the waste liquor to miniature photofinishing laboratories because of its low collection efficiency, thus causing problems such that shops are full of waste liquor.
For the purpose of solving these problems and with an aim of making it possible to readily carry out the treatment of the photographic process waste liquor also in the miniature photofinishing laboratories, it has been researched to heat the photographic process waste liquor to carry out evaporation of water to dryness or effect solidification as disclosed, for example, in Japanese Utility Model Unexamined Publication No. 70841/1985.
Incidentally, in the case where the photographic process waste liquor is treated by evaporation, harmful or remarkably ill-smelling gas such as sulfur dioxide, hydrosulfide and ammonia gas are generated. This is caused by decomposition of sulfur series compounds used for or particular to the fixing solution and bleach-fixing solution contained in the photographic process waste liquor, for example, thiosulfates, sulfites, etc.